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A strength of the book is the chapters on 'Transposition Mechanisms' and on 'Retrotransposon Transcription and its Control'. It becomes obvious that one of the authors contributed important studies on the molecular mechanisms of retrotransposition in Drosophila. An important issue is also that the authors consistently use the terms LTR-retrotransposons and non-LTRretrotransposons and not the confusing terms retroposons and LINES. There are negative aspects to the book as well, and some carelessness in a number of substantial details could have been avoided. For example, Table 2.2 Co. 11) in which the conserved domains of all known Drosophila LTR-retrotransposons are aligned, leaves out the integrase domain Hx4Hx~CrFCxn#~GQVER of the mlcropla retrotransposon. There is also no reason why the blastopia retrotransposon should have been ignored in this chapter. Additionally, an alignment of the domains of the non-LTRretrotransposons would have been useful.
The figures also could have been a little better presented (some oriented differently, some smaller, some better drawn). The chapter I disliked was on 'Retrotransposons and Genetic Instability'. The data accumulated on this topic are poor and their interpretations sound quite myt~caL Some of the problems encou~te~l with 'transposon-burst sysL~.a~s' a~'e discussed elsewhere by Engels 4and the interested reader might want to refer to this. Also, the Penelope transposon does not encode an aspartic protease but instead encodes an RNA-or DNA-dependent polymerase and no RNase-H 0Vi.Evgen'ev et aL, unpu01ished). Nevertheless, this chapter should be taken as an example of how difficult it is to study such . complex processes as transposon bursts, and how easily wishful thinking takes over. The interdependency of TART reverse transcriptase and HeT-A element transposition might be a more fruitful approach for these phenomena.
The Bible- 20 yea on
research interest to see how it is described. ! must confess that I was somewhat disappointed in the coverage of the regulation of gone expression. The first edition contained chapters ,entitled 'Control of gone e~pression' and 'Eucaryotlc chromosomes'. Obviously, at that time :e!aUvely little was known about the control of eukaryotlc gene expression and so it was barely dealt with. The vast array of information that has accumulated on this topic has been recognized in the new edition by re,naming these chapters 'Control of gone ~presslon in prokaryotes' and 'Eukaryotic chromosomes and gone expression'. Apart from the change in the spelling of eukaryotic, the latter chapter also includes much material on transcription factors, wkilst their specific binding sites in gone regulatory regions are dealt with in an earlier chapter on RNA synthesis. Nowhere, however, is there an indication of how transcription factor synthesis or activity is regulated so as to produce the specific activation of individual genes in particular cell types or in response to particular stimuli, which is fundamental to cell-type-specific gone expression and differentiation. Indeed, the only place where this is hinted at, on page 857, contains an error: the text indicates that 'A heat shock transcription factor is expressed in Drosophila following an abrupt increase in temperature'. In fact, the heat shock factor is present in unstressed cells in an inactive form and is activated posttranslatlonally following the heat stress. These are, of course, minor caveats
Biochemistry(4th edn) by D~r¢ ~ e r , W. H. Freeman, 1995. $29.95 (xxxiv+ 1064 pages) ISBN0 7[672009 4 It is now 20 years since the first edition of Stryer's Biochemistry was published. As an undergraduate student at that time. 1 wall remember being tremendously excited by this first edition and by the (then novel) feature of the numerous colour diagrams, Indeed, ! do not think ! would have been able to come to grips with the mechanisms of enzyme catalysis without the clear text and pictures provided by Stryer, In reviewing the recently pub,shed fourth edition, one feels somewhat apprehensive at commenting on what has become the bible of successive generations of biochemistry undergraduates. Of course, overall the new edition does not dlsappolnt. The clarity of exposition and the elegance of the diagrams are. as always, outstanding. Moreover, considerable advantage has been taken of the Increasing amount of structural Information that is now becoming available from crystallographic methods, and numerous elegant reproductions of such structures are included, However, it is only natural that in reviewing a vast work such as this, one should turn to the area of one's own
Despite these few glitches the book finishes brilliantly with a very nice discussion of an idea first suggested by Mathew Meselson, of a possible role for transposons in the evolution and maintenance of sex in eukaryotes. Here, even the most hard-headed sceptic should now be convinced of the importance and relevance of transposons, not only in Drosophila, but in all ~anismso References 1 McDonald,J. F. (1993) in Transposable Elementsand Evolution(McDonald,$. F., ed.), pp. 1-4, K~uwerAcademicPubfishers 2 Rnnegan,D. J. et at. (1978) ColdSpringHarbor Syrup. Quant. Biol. 42,/053=1063 3 llyin,Y. V. et aL (1978) ColdSpringHarbor ~mp. QuanL Blot,42, 959=969 4 Engels,W. O. (1989) in MobileDNA(Berg,O. E. and Howe,M. M., eds), pp. 437=484, ASMPress DIRK-HEHHER OJ~NKENAU Departmentof DevelopmentamGenetics,German CancerResearchCenter,D69120 HeideOberg, Germany.
that do not detract from the value of the work as a whole. It is an amazing achievement to have produced a new edition of this work containing all the advances that have been made over the last 20 years and yet deal with these in a work that is less than 20% longer than the original text. No doubt 'Stryer' wlll rema!n the bible for bi~che~istry undergraduates fol" many more years to come. However, they may have to go elsewhere for some of the detailed commentary.
DAVIDS. LATCHMAN Departmentof MolecuOarP.atholo~y, UniversityCollegeLondonMedicagSchool, London,UK W1P6DB.
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